New removable mag idea
The mag slides through the other layers like a rail system (see pic 2-4). Then when you fire the firing pin keeps the mag in place (pic 5).
The mag also has a long hole on one side so that the mag pusher doesn't have to have a long stick going out of it. That's the new idea so anyone can use it now if they give credit to me. =)=) (i also give credit to the jamalam)